1. Field of the Invention
Embodiments of the present invention are directed to a system and a method for dewatering slurries. In more detail, embodiments of the present invention are directed to a customizable dewatering system that can be efficiently erected to perform dewatering operations for slurries obtained from dredging or from other waste removal operations.
2. Description of the Related Art
Dewatering is one of the biggest obstacles facing dredging operations around the globe. Previously, common dredge discharge areas were constructed by hauling in dirt and constructing an earthen-wall containment cell to decant dredged materials (hereinafter referred to as “slurry” or “slurries”) that have been dredged from a body of water. The silt, sand, or sediment (hereinafter referred to as “solid material”) in the slurry would settle to the bottom of the containment cell, and the resulting clarified water (forming on top of the settled, solid material) could be decanted at the appropriate time through a weir-box release system or decanting pipe. However, this is a time consuming and expensive process.
Another previously-used form of dewatering slurries is through the use of containers comprised of synthetic-woven fabric formed into a tube. A dredge discharge pipe or hose can be connected to ports on top of the tube, and the tube can be filled with the slurry. The solid material from the slurry settles in the tube and clarified water filters through the fabric. However, this process usually requires dozens of tubes to be filled in parallel using a manifold that diverts the flow of the slurry through a series of knife valves. Polymers can be added to increase the dewatering rate and to settle out solid material faster. Nevertheless, polymers are expensive and usually require an auto-injector system which calibrates the right quantity of polymer to match the charge of the solid material (or, alternatively, an onsite chemist may be required to perform this work manually). Such synthetic-woven fabric tubes are a common method for dewatering slurries, but they are expensive and are not re-usable.
Another previously-used dewatering process includes the use of mechanical dewatering systems that are road transportable and contain a series of de-sanders, de-silters, and hydro-cyclones. These systems can match the slurry feed of a dredging system and are scalable. Furthermore, these systems can be used to dewater slurries down to 25 microns. Nevertheless, they require additional clarifying technologies to remove smaller particles (usually fine organics under 25 microns) from clarified water. However, these systems are quite complex and expensive. For instance, the cost for such a complete mechanical dewatering system can range from between $500,000 to $4,000,000.
As such, there is a need for a dewatering system with a reduced complexity, which allows the dewatering system to be erected in an efficient manner, with a small footprint, and at generally any location as may be necessitated by dredging operations. Additionally, there is a need for a dewatering system that can be manufactured at a reasonable price to accommodate its use for dredging operations performed throughout the world, such as in third-world countries that may not have the financial resources to obtain other, high-priced dewatering systems (e.g., the mechanical dewatering system described above).